$7jk + 7jl - 6j + 4 = -9k - 9$ Solve for $j$.
Explanation: Combine constant terms on the right. $7jk + 7jl - 6j + {4} = -9k - {9}$ $7jk + 7jl - 6j = -9k - {13}$ Notice that all the terms on the left-hand side of the equation have $j$ in them. $7{j}k + 7{j}l - 6{j} = -9k - 13$ Factor out the $j$ ${j} \cdot \left( 7k + 7l - 6 \right) = -9k - 13$ Isolate the $j$ $j \cdot \left( {7k + 7l - 6} \right) = -9k - 13$ $j = \dfrac{ -9k - 13 }{ {7k + 7l - 6} }$ We can simplify this by multiplying the top and bottom by $-1$. $j= \dfrac{9k + 13}{-7k - 7l + 6}$